In the original Dungeons & Dragons pamphlets, this breed of demon was known as "balrog",[4] but the name was revised in subsequent supplements to simply "type VI demon" so as not to infringe on J. R. R. Tolkien's copyright.[citation needed] In second edition AD&D, the name "type VI demon" was revised to "balor," taking the name of the greatest individual of their rank as the name for the entire breed.[5] Also in second edition, balors now had vorpal swords.[6]

The type VI demon (Balor, etc.) appears in the first edition Monster Manual (1977).[8] In this incarnation of the game there were only six Type VI Demons in existence across all of the planes of the multiverse, and they were ranked in power below only the Demon Lords and Princes of the Abyss, who were each unique in both name and form. Each Type VI Demon had its own individual name as an indication of their importance and power, as lesser demons (Types I - III and lower) had only a species name, and not individual appellations. Their names were listed in an appendix of the Dungeon Master's Guide, given as: Errtu, Ndulu, Ter-Soth, Alzoll, and Wendonai, with Balor itself being the greatest and most powerful of them all.[9]

This edition of the D&D game included its own version of the type VI demon, which is known as the roaring demon, first appearing in the Immortal Rules set, in the DM's Guide to Immortals (1986).[10] The roaring lesser fiend appeared in the Wrath of the Immortals set, in "Book One: Codex of the Immortals" (1992).[11]

In this edition, demons were reintroduced in the Outer Planes Appendix of the Monster Compendium, relabeled as tanar'ri, and the Type I through VI designations were dropped in favor of a species name for each type. This creature officially became known as the balor, a "true tanar'ri", taking the name of the most powerful of the Type VI Demons as the species name for the entire breed and removing much of their individuality. (1991),[12] and then reprinted in the Monstrous Manual (1993).[13]

The balor true tanar'ri also appeared for the Planescapecampaign setting in the first Planescape Monstrous Compendium Appendix (1994).[14] Balors were most often no longer given individual names in print, usually referred to simply as "a balor demon" or similar, and their numbers were increased drastically, from only six in existence to perhaps hundreds of thousands or more, as the plane they inhabited, the Abyss, was said to be composed of an infinite number of infinite layers (or alternately, 666 infinite layers) and the numbers of tanar'ri were likewise said to be infinite. Balors were no longer ranked just below the Demon (now Tanar'ri) Lords and Princes, and several other types of non-unique tanar'ri were introduced above them, such as the molydeus.

The balor appears in the Monster Manual for this edition (2000);[15] In this edition, the name demon is resumed, with tanar'ri now being considered a subtype of related demons. The tanar-ri were now said to have been created by another, older subtype of demon, the obyrith, and any native inhabitant of the Abyss is referred to as a demon. The relative power level of the balor remains the same as previously in 2nd Edition, but now allowance is made for varying power levels within the balor type, with increased size and hit dice possible, and even the possibility of a balor having character class levels (such as levels of Fighter or Sorcerer added on top of the native power of a balor itself.) Balors are once again routinely given individual names in print in many instances (such as Errtu and Wendonai once again making appearances) and much of their individuality is restored, with class levels and varying hit dice being listed for individual balors (such as the aforementioned Wendonai, who is given game statistics including class levels, and even a prestige class.)

In the original Monster Manual, balors are 12-foot-tall (3.7 m), winged humanoids with horns and demonic features. They prefer to wield swords and many-tailed whips. They are able to create flames around themselves and shed darkness at will. They possess a strong charisma that attracts other chaotic evil creatures. They tend towards organized evil. Six balors are known to exist, in the game's first edition.

In the 2nd edition Monstrous Manual, balors are the most powerful tanar'ri. They exist solely to wage the Blood War, and roam the Abyss, forming legions to command in battle. They have huge wings, claws, venomous fangs, and are frequently surrounded by flame. They wield a many-tailed whip and a greatsword that resembles a bolt of lightning. In the game's second edition, at least 24 balors are known to exist.

In third edition version of the Monster Manual, balors are 12-foot-tall (3.7 m) humanoids with bat wings, bull horns, clawed hands, and a mane. Their dark red skin is bathed in flame. They wield a vorpal sword in one hand and a flaming whip in the other. They are generals of demonic armies. They answer only to Demon lords and kluritchirs.

Balors are among the most powerful demons of the abyss, surpassed only by the demon lords. In the 3rd Edition Fiend Folio, two types of Tanar'ri, kluritchirs and myrmyxicus, are more powerful than balors. There are exceptional lesser demons that may surpass a balor, but few possess more potential.

Wendonai - detailed in Lost Empires of Faerun, pages 54–55. He is a former favorite of the drow goddess Lolth and specializes in the art of corruption. He was instrumental in the fall of the drow.

Other balors:

Belial - a Balor summoned in Chapter Two of Neverwinter Nights in the "Village of Eternal Night" quest. He was responsible for the slaughter of the children of Charwood alongside Karlat Jhareg. Entitled "Lord of Fire" and 'Prince of Demons".